Youngsters cannot receive the jab until they are two months old. Vaccinating their mothers before they are born will boost their immunity until they reach the age when they can have the injection themselves, she said.

Women across the UK who are between 28 and 38 weeks pregnant are being offered the vaccination.

Increases in whooping cough are usually seen every three to four years. The last rise in the number of confirmed cases was recorded in 2008.

Dr Gayatri Amirthalingam, consultant epidemiologist for immunisation at the HPA, said: "We strongly recommend all pregnant women take up the offer of vaccination."

In the very young, whooping cough can be a serious illness and can lead to death in some cases.

Babies and children can often make a distressing "whoop" sound while gasping for air after a coughing fit.

Professor David Salisbury, director of immunisation at the Department of Health, said: "Whooping cough is highly contagious and infants are particularly vulnerable."

He said there had been nearly 400 cases of the disease in children under three months old this year.